1. Field of the Invention
The present invention relates to a flexible endoscope part.
2. Description of the Related Art
An endoscope comprises an insertion part which is inserted into a tubular cavity, and a flexible part which is operated to curve is provided at a top end of the insertion part. The flexible part comprises a flexible tube which forms a skeletal structure of the flexible part.
Jpn. UM Appln. KOKOKU Publication No. 38-46801 discloses a flexible tube. In the flexible tube, number of joint rings are substantially coaxially connected sequentially in a mariner that the joint rings are pivotable in relation to each other.
Specifically, in the joint rings each, a pair of tongue parts is provided to protrude at each of two ends of a cylindrical part. An axial hole is formed to penetrate each tongue part in a radial direction. For each two adjacent joint rings, a pair of tongue parts of one of the adjacent joint rings and a pair of tongue parts of the other of the adjacent joint rings are layered on each other in radial directions, and a joint shaft is inserted through the axial holes of the tow pairs of tongue parts. The joint shafts each are provided with a pair of gap parts extending throughout a whole circumference of the joint shaft substantially in radial directions of the joint shaft. Two tongue parts are sandwiched by both gap parts of the joint shaft, to be pivotable in relation to each other about the joint axes each. Further, inner ends of each joint shaft in the radial directions are protruded to inside of the joint rings. Wire insertion holes are formed to penetrate the inner ends of the joint shafts in the radial directions of the flexible tube. Angle wires are inserted through the wire insertion holes, and top ends of the angle wire are fixed to the top ends of the insertion part. The flexible part can be operated to curve by pulling/operating the angle wire.
In the flexible tube according to Jpn. UN Appln. KOKOKU Publication No. 58-46801, the joint shafts each are formed of a rigid member and do not substantially deform. Therefore, when the flexible part is operated to curve by pulling/operating the angle wires, there is a case that resistance against a pulling operation of the angle wires increases and causes difficulties in smoothly operating the flexible part, depending on a positional relationship between the angle wires and the joint shafts and conditions of load from the angle wires to the joint shafts. In addition, the joint shafts each are formed by cutting/processing a rod-type rigid material, and are therefore difficult to manufacture at low costs. Since the pair of gap parts of each joint shaft sandwich two tongue parts, work of attaching the joint shafts to the joint rings is complicated. Therefore, there are difficulties in manufacturing the flexible part at low costs.
The invention has been made in view of the problems as described above and has an object of providing a flexible endoscope part, which can be smoothly operated to curve and can be manufactured at low costs.